This invention relates to an apparatus and method for internally reinstating a connection in a lined conduit, and more particularly to the internal reinstatement of a service in a conduit that has an installed corporation stop.
A variety of circumstances exist in which it is desirable to form a junction or branch line from a main, fluid-carrying conduit. For instance, in the municipal area, it is often necessary to install a branch line into a water main, gas main or sewer main. A similar need exists in other industries, such as in the chemical pipeline industries.
In the municipal area, many water mains were constructed years ago and the wall structures are now badly eroded or collapsing. In order to repair such damage, it has been proposed to install a liner within these lines to provide a new water-impervious wall to the system. There are a wide variety of different methods available in the art for inserting liners within existing conduits. These lining methods include the cured-in-place, fold-and-form and diameter reduction methods, each of which inserts a liner from one end of the conduit to the other. However, the wall of the line is usually not continuous since branch lines and service connections intersect the main conduit at various entry ports to allow the free flow of fluid from the main to the branch service line. In the case of existing and newly formed entry ports, it is desirable to utilize a corporation stop at the junction to control the fluid on either a temporary or a permanent basis.
It is desirable to reinstate the connection internally after the lining operation. To be successful, the reinstatement must form a seal between the reconnection member and the lining and between the reconnection member and the branch or service connection.
In the case of service connections, there are a variety of corporation stops in the prior art. All suffer from some deficiency. Many of the prior art assemblies are complicated in design and are time consuming to install. Standardized machinery has been developed for installing corporation stops in conduits carrying fluid under pressure, such as the B-101 drilling and tapping machines manufactured by Mueller Co. However, this machinery is not well suited for use with a conduit that has been lined or rehabilitated with a synthetic liner.
A prior art corporation stop assembly that is specifically designed for installation in a conduit lined with a synthetic liner from the outside is disclosed in U.S. Pat. No. 5,199,145 to McMillan et al. While entirely suitable, such method requires excavation of the buried conduit to install the connection externally. The McMillan et al. corporation stop has a flexible sleeve member and a threaded stem with an enlarged head portion, and is installed into the lined conduit by way of a clamp nut that engages the neck portion of the threaded stem for forcibly moving the lower end of the sleeve member over the head portion of the stem to expand the lower end of the sleeve member inside the conduit to form an internal seal with an opening in the conduit.
Another example of an external tap being installed from the outside of the conduit is disclosed in U.S. Pat. No. 5,737,822 to Driver et al. They disclose a corporation stop assembly for use with standard tapping equipment including a threaded stem with an enlarged, conical head for forming a blind side seal. A standard saddle having a radially-inward tab is placed on the external sidewall of the conduit about the opening and receives the compression ring, the tab engaging the notch in the compression ring. The stem, saddle member and compression ring engage each other to prevent relative rotation during installation.
While these devices allow for installation of a connection in a lined conduit, they require external access to the connection joint. Accordingly, it is desirable to provide an improved method and apparatus to reinstate a connection internally to avoid the need to excavate at each connection.